天然牙-种植体共同支持式固定义齿的生物力学研究Ⅰ.垂直集中载荷对种植体、天然牙骨界面应力的影响

目的:通过对天然牙-种植体共同支持式固定义齿受垂直集中载荷时,种植体、天然牙骨界面应力分布情况进行测试,为临床能否使用该方式修复牙列缺损提供生物力学的理论依据。方法:应用电阻应变计电测技术的方法。结果:天然牙-种植体共同支持式固定义齿修复时,在垂直集中载荷下,随着载荷的不断加大,天然牙-种植体与骨组织界面处的应力值不断加大,最大应力出现在种植体、天然牙根颈部区,种植体与稳固的天然牙共同支持式固定修复时,天然牙与骨界面应力分布较均匀。结论:从生物力学的角度来看,在优化临床设计的前提下,天然牙-种植体共同支持式固定义齿是临床可采用的特殊固定义齿,尤其适用于末端游离缺牙的患者。     

种植体与天然牙联冠修复应力分布的三维有限元分析I．垂直集中载荷对种植体、天然牙骨界面应力的影响

目的：探讨种植体与天然牙联冠修复在垂直集中载荷作用下,种植体、天然牙骨界面应力分布情况及受力的相互影响,为临床优化设计提供生物力学的理论依据。方法：采用三维有限元法建立模型并计算、分析。结果：种植体与天然牙联冠修复时,种植体、天然牙骨界面颈部和根尖部出现应力集中;种植体与稳定的天然牙联合修复时种植体－骨界面应力分布较均匀。结论：种植体与天然牙可共同承担载荷;当天然牙受垂直集中载荷时,种植体未过载;种植体最好与稳定的天然牙联合修复。     

种植体与天然牙联冠修复应力分布的三维有限元分析1.垂直集中载荷对种植体、天然牙骨界面应力的影响

目的探讨种植体与天然牙联冠修复在垂直集中载荷作用下,种植体、天然牙骨界面应力分布情况及受力的相互影响,为临床优化设计提供生物力学的理论依据.方法采用三维有限元法建立模型并计算、分析.结果种植体与天然牙联冠修复时,种植体、天然牙骨界面颈部和根尖部出现应力集中;种植体与稳定的天然牙联合修复时种植体-骨界面应力分布较均匀.结论种植体与天然牙可共同承担载荷;当天然牙受垂直集中载荷时,种植体未过载;种植体最好与稳定的天然牙联合修复.     

种植体与天然牙联冠修复应力分布的三维有限元分析 Ⅰ.垂直集中载荷对种植体、天然牙骨界面应力的影响

目的 :探讨种植体与天然牙联冠修复在垂直集中载荷作用下 ,种植体、天然牙骨界面应力分布情况及受力的相互影响,为临床优化设计提供生物力学的理论依据。方法 :采用三维有限元法建立模型并计算、分析。结果 :种植体与天然牙联冠修复时 ,种植体、天然牙骨界面颈部和根尖部出现应力集中 ;种植体与稳定的天然牙联合修复时种植体-骨界面应力分布较均匀。结论 :种植体与天然牙可共同承担载荷 ;当天然牙受垂直集中载荷时 ,种植体未过载 ;种植体最好与稳定的天然牙联合修复     

种植体与天然牙联冠修复应力分布的三维有限元分析Ⅱ.水平集中载荷对种植体、天然牙骨界面应力的影响

目的 :探讨种植体与天然牙联冠在水平集中载荷作用下 ,种植体、天然牙骨界面应力分布情况及受力的相互影响 ,为临床优化设计提供生物力学的理论依据。方法 :采用三维有限元法。结果 :种植体与天然牙联冠修复时 ,种植体、天然牙骨界面颈部应力集中明显 ;种植体与稳定的天然牙联合修复时种植体 -骨界面应力分布较均匀。结论 :种植体与天然牙可共同承担载荷 ;但侧向力对种植体影响较大 ,在修复设计上应采取相应减小侧向力的措施。     

天然牙-游离端叶状种植体联合固定义齿三维有限元研究：Ⅲ．底层支架材料对应力传递的影响

用3D-FEM研究了上部修复材料弹性模量大小对天然牙-游离端叶状种植体联合固定义齿应力传递的影响，结果发现：分散载荷时，天然牙上所受到的力有一部分通过上部支架传到种植体上，并且随着修复材料弹性模量的增大传递的力也增大，但增大很少；集中载荷时金塑固定义齿较全塑固定义齿更有利于分散种植体上受到的力，应力分布更均匀。     

天然牙-牙种植体联合固定义齿

天然牙-牙种植体联合固定义齿是目前临床常见的修复方式，但争议较大。本文结合近年文献，简单概述了联合固定义齿中两种基牙的力学性能差别、联合修复时的应力分布特点、各种改善联合固定义齿应力分布的措施及相关研究。     

天然牙-游离端叶状种植体联合固定义齿三维有限元研究：Ⅱ．对集中载荷的应力分析

采用3D-FEM分析天然牙-游离端叶状种植体联合固定义齿在集中载荷条件下的应力、位移规律，结果发现：垂直集中加载时，天然基牙的最大位移小于种植基牙，且二者相差较大；远中天然基牙的近中颈部牙周膜处有应力集中区；种植体近中桩颈部的应力水平高于远中桩颈部；种植体适中桩颈周皮质骨界面有应力集中。     

天然牙─游离端叶状种植体联合固定义齿三维有限元研究──Ⅲ.底层支架材料对应力传递的影响

用3D－FEM研究了上部修复材料弹性模量大小对天然牙一游离端叶状种植体联合固定义齿应力传递的影响，结果发现：分散载荷时，天然牙上所受到的力有一部分通过上部支架传到种植体上，并且随着修复材料弹性模量的增大传递的力也增大，但增大很少；集中载荷时金塑固定义齿较全塑固定义齿更有利于分散种植体上受到的力，应力分布更均匀。     

天然牙与种植体联合支持修复牙列缺损的研究进展

天然牙与种植体联合支持固定桥修复,为临床上有效修复牙列缺损提供了更多选择,但一直存在争议。有学者认为,天然牙与种植体联合支持固定桥在临床上是一种相对简便、经济、实用、有效的修复方式,天然牙与种植体联合支持固定桥修复远期效果良好,临床上可行。也有学者认为,种植体与天然牙联合修复未必是理想的选择,应尽量避免,当条件有限,无法行种植体支持固定桥修复时可选择应用。天然牙与种植体联合支持可摘局部义齿修复,种植体在缺牙远端的应用可以将可摘局部义齿形式由基牙-黏膜支持式转换为天然牙-种植体支持式,成功率较高。总之,当口内两单位以上牙列连续缺损时,种植体支持固定修复应为最佳选择;当受主客观条件所限难以实现时,可以行天然牙和种植体联合支持。     

Evidence of the validity of a model of determinants of quality of restorative dental care

A model describing the relationship between self-reported quality of restorative dentistry and dentist characteristics for 119 Montana general dentists is presented. The best predictors formed a significant model explaining 22% of the variance of the quality measure. Results are contrasted with a previous estimation of the model for 102 Washington general practitioners. Evidence for the external validity of the model is presented.     

Experimental evidence of formation of imines in the course of reduction of hydrazones

The reduction of hydrazones is generally suggested to proceed through a reductive cleavage of the nitrogen–nitrogen bond followed by a reduction of the carbon–nitrogen bond. This sequence of reduction processes is here supported for fluorenone (V) and benzophenone (VI) hydrazones as well as by a comparison of the reduction of fluorenone and benzophenone hydrazonium ions (I,III) with corresponding imines (II,IV). Another proof of the presence of imines as intermediates is the splitting of four-electron waves of hydrazones V and VI and hydrazonium ions I and VIII into two waves at pH < 2. This has been interpreted as due to differences in slopes dE_1/2/dpH and pK_a-values of protonated hydrazine derivatives on one side and corresponding imines on the other. In this pH-range imines formed in reductions of VI and VIII are reduced in a single two-electron wave, those of I and V in two one-electron steps. Fluorenone imine (II) is sufficiently stable to allow recording of time-independent current–voltage curves between pH 6 and 11. In this pH-range the imine (II) is reduced in two one-electron steps. Benzophenone imine (IV) has been found stable between pH 4.6 and 12. At pH 4.6–8 the reduction of the imine IV takes place in a single two-electron step, at pH 8–12 in two one-electron steps. Final proof of the initial cleavage of the N–N bond is presented by comparison with the reduction of nitrones.     

不同剂型玻璃离子水门汀溶解性比较研究

目的:研究、比较不同剂型玻璃离子水门汀的溶解性和表面微观形态改变,为临床使用提供依据.方法:将3M树脂加强型玻璃离子水门汀(水粉剂型)、GC玻璃离子水门汀(水粉剂型)及GC玻璃离子水门汀(双糊剂型)分别在人工唾液中浸泡30 d,冷热循环15000次,烘干测重,比较前后质量变化,计算溶解率,并用扫描电镜观察表面微观改变.结果:不同剂型的玻璃离子水门汀溶解率由高到低分别为3M树脂加强型玻璃离子水门汀(水粉剂型)、GC玻璃离子水门汀(水粉剂型)、GC玻璃离子水门汀(双糊剂型).3种玻璃离子水门汀经浸泡溶解后,SEM扫描表面微观形态可观察到GE玻璃离子水门汀(双糊剂型)表面形态改变较少,其他2组玻璃离子水门汀表面微观改变较多.结论:双糊剂型玻璃离子水门汀理化性能及溶解率均低于传统水粉剂型,是未来临床修复治疗的的良好选择.     

Evaluation of efficacy of chemiluminescence for diagnosis of leukoplakia

ObjectiveLeukoplakia is the most common potentially malignant disorder preceding oral cancer. Chemiluminescence has been developed as an adjunct to conventional examination for the diagnosis of these potentially malignant disorders. This study was conducted to assess the efficacy of chemiluminescence in the diagnosis of leukoplakia and to compare the results with histopathological examination.Study designA total of 50 patients with leukoplakia were included from the outpatients attending the Department of Oral Medicine and Radiology, Dental Hospital, Bengaluru, Karnataka, India. These patients were subjected to conventional oral examination followed by chemiluminescent examination with Vizilite (Zila, Fort Collins, CO, USA) and biopsy for histopathological confirmation.ResultsThe sensitivity, specificity, positive predictive value, and negative predictive value of chemiluminescence were 93.75%, 55.56%, 78.95%, and 83.3%, respectively. The overall accuracy of chemiluminescence was 80%. A statistically significant association was observed between histopathology results and chemiluminescence results.ConclusionAlthough it is an easy, safe, minimal time consuming, and noninvasive technique, it has only adjunctive utility and it does not replace biopsy for the diagnosis of leukoplakia.     

颌骨动静脉畸形的栓塞治疗

目的：总结直接穿刺结合经血管内介入栓塞治疗颌骨动静脉静脉畸形的经验。方法：收治凳骨动静脉畸形患者6例,均进行了介入栓塞治疗。采用的栓塞材料为附凝血棉纤毛的螺圈,聚乙烯醇泡沫微粒和二氰基丙烯酸对丁酯。数字减影颈动脉造影在PHILIPSV300下完成。结果6例颌骨动静脉畸形患者中4,例急性出血得到了快速、有效控制,1例慢性渗血的右下 骨动静脉畸形患者,介入栓塞治疗,拔除松动的右下凳第一磨牙,有效地控制了出血,另1例伴局部软组织搏动性膨隆的上凳骨动静脉畸形患者,介入治疗后膨隆的搏动性得到明显改善,栓塞治疗后分别随访3－24个月,均未发现有口腔内渗血或出血。随访的X线片上,病灶区可见新骨形成。结论：局部穿刺结合经血管内介入栓塞治疗颌骨动静畸形是一种安全、有效的治疗方法。     

正畸患者切牙影像失真发生情况分析

目的研究正畸患者曲面体层片上的切牙影像失真发生情况，并分析其原因。 方法从中山大学附属口腔医院放射科影像数据库中选取500例正畸患者的曲面体层片和头影测量侧位片，所有曲面体层片均采用咬合杆投照，分别从切牙牙体影像放大、缩小、牙根变短、根尖模糊等评价指标分析上下颌切牙影像失真的发生情况，在头影测量侧位片上测量中切牙根尖-对颌切牙切缘的距离，探讨切牙影像失真发生的原因。采用SPSS 19.0统计软件对所得数据进行统计学检验。 结果500例患者中，切牙牙体影像正常者共417例，切牙牙体影像失真者共83例，影像失真发生率16.6%，其中切牙牙体影像放大17例、牙体影像缩小0例、牙根变短30例，牙根影像变短伴模糊36例。影像失真患者的根尖-切缘距离大于影像正常的患者，差异有统计学意义（F = 5 187.18，P = 0）；影像失真患者的覆盖值大于影像正常的患者，差异有统计学意义（F>477，P = 0）。 结论严重牙颌面畸形如反 、深覆盖是导致曲面体层片的切牙影像失真的主要原因之一。     

Design of clinical trials of traditional therapies of periodontitis

The present paper on the design of clinical trials of periodontal therapy first addresses the issue of the etiology of periodontal disease. It is suggested that most if not all forms of destructive periodontal disease are caused by microorganisms and that there are different forms of disease with different microbial etiologies. The progressive nature of destructive periodontal disease is subsequently discussed and it is emphasized that, in a given patient, periodontal sites which show signs of inflammation and attachment loss may not over a period of several months and years show further sign of attachment loss. The present methods of assessing periodontal disease do not allow us to discriminate between potentially active and inactive sites in untreated patients. The significance and variability of indicators of periodontal disease such as bleeding on probing, probing pocket depth and probing attachment level measurements are discussed. The errors inherent in the various measurements are analyzed and suggestions are presented describing how alterations in any of the above parameters could be identified and presented in a clinical trial. Of concern for the statistical analysis of clinical data of periodontal disease is the definition of the "experimental unit". For a number of years, the "experimental unit" in periodontal trials was the patient. It is clear, however, that different sites within the same individual show different patterns of disease progression and lesion morphology and often respond differently to periodontal therapy. Statistical analyses must consequently be designed which recognize differences in site-to-site infection and lesion morphology within a common host. Until such analyses are available, the investigator should be wary of pooling data within the same individual, since such pooling may obscure meaningful alternatives which may take place in individual periodontal sites. Some goals of periodontal therapy are subsequently identified. 4 goals are discussed more in detail, namely: to establish conditions which will allow the patient to maintain a dentition without further breakdown of the periodontium; to reduce pocket depth to establish an anatomy in the dentogingival region which with proper maintainance care will prevent the re-establishment of the subgingival infection; to gain attachment as a result of treatment; to assess the effect of a certain chemotherapeutic agent on periodontal disease.     

正常青年Monson球面半径的测量研究

目的测量正常青年Monson球面半径。方法选择60名(男30名,女30名)正常青年制取全口印模,应用立体摄影成像的原理与方法对Monson球面半径进行测量和统计学处理。结果Monson球面的半径平均为10.173 cm,大于理论值10.160 cm,差异有显著性(P<0.01);男、女性球面半径差异无显著性。结论本实验所得到的数据可作为全口义齿修复中记录颌位关系的一个参量。     

鼻测量法的进展

唇裂术后继发畸形是指唇裂修复术后,仍遗留或继发于手术操作和生长发育变化而表现出来的一类畸形[1]。包括唇畸形、鼻畸形和颌骨畸形。其修复较原发性唇裂修复更复杂,更灵活多变。而导致其修复复杂性的一个重要原因即是局部组织结构复杂变异和缺乏可靠的三维测量手段[2],鼻畸形     

口底癌34例临床分析

目的探讨口底癌的临床特性、治疗方法及预后。方法对我院自1992—2002年住院治疗的34例口底癌患者进行回顾性分析。结果34例口底癌患者中,男28例(82.4%),女6例(17.6%),男女比为4.7∶1,平均发病年龄58岁。发病部位:前口底22例(64.7%),后口底12例(35.3%)。淋巴结转移率41.2%。单纯手术组、化疗加手术组、放疗加手术组、化疗加手术加放疗组的5年生存率分别为45.5%、60.0%、50.0%、62.5%。结论口底癌以中老年患者好发,男性居多。易发生淋巴结转移,综合疗法疗效较好。